llvm-6502/lib/Target
Evan Cheng beb07e117d A big more cleaning up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26302 91177308-0d34-0410-b5e6-96231b3b80d8
2006-02-21 19:30:30 +00:00
..
Alpha improved zap discovery 2006-02-13 18:52:29 +00:00
CBackend Another hack due to allowing multiple symbols with the same name. 2006-02-13 22:22:42 +00:00
IA64 distinguish between objects and register names, now we can have stuff 2006-02-16 13:12:57 +00:00
PowerPC Moved PICEnabled to include/llvm/Target/TargetOptions.h 2006-02-18 00:08:58 +00:00
Skeleton Remove the skeleton target, it doesn't produce useful code and there are 2006-02-16 23:14:50 +00:00
Sparc The HasNoV9 hack isn't needed here, now that tblgen knows that CustomDAGSchedInserter 2006-02-21 18:04:32 +00:00
SparcV8 Remove the SparcV8 backend. It has been renamed to be the Sparc backend. 2006-02-05 06:33:29 +00:00
SparcV9 Adjust to MachineConstantPool interface change: instead of keeping a 2006-02-09 04:46:04 +00:00
X86 A big more cleaning up. 2006-02-21 19:30:30 +00:00
Makefile
MRegisterInfo.cpp Finegrainify namespacification 2006-02-01 18:10:56 +00:00
README.txt missed optzn 2006-02-21 18:29:44 +00:00
SubtargetFeature.cpp Improve compatibility with VC2005, patch by Morten Ofstad! 2006-01-26 20:41:32 +00:00
Target.td Added x86 integer vector types: 64-bit packed byte integer (v16i8), 64-bit 2006-02-20 22:34:53 +00:00
TargetData.cpp
TargetFrameInfo.cpp
TargetInstrInfo.cpp
TargetMachine.cpp
TargetMachineRegistry.cpp
TargetSchedInfo.cpp
TargetSchedule.td Add a default NoItinerary class for targets to use. 2006-01-27 01:41:38 +00:00
TargetSelectionDAG.td kill ADD_PARTS & SUB_PARTS and replace them with fancy new ADDC, ADDE, SUBC 2006-02-17 05:43:56 +00:00
TargetSubtarget.cpp

Target Independent Opportunities:

===-------------------------------------------------------------------------===

FreeBench/mason contains code like this:

static p_type m0u(p_type p) {
  int m[]={0, 8, 1, 2, 16, 5, 13, 7, 14, 9, 3, 4, 11, 12, 15, 10, 17, 6};
  p_type pu;
  pu.a = m[p.a];
  pu.b = m[p.b];
  pu.c = m[p.c];
  return pu;
}

We currently compile this into a memcpy from a static array into 'm', then
a bunch of loads from m.  It would be better to avoid the memcpy and just do
loads from the static array.

===-------------------------------------------------------------------------===

Get the C front-end to expand hypot(x,y) -> llvm.sqrt(x*x+y*y) when errno and
precision don't matter (ffastmath).  Misc/mandel will like this. :)

//===---------------------------------------------------------------------===//

Solve this DAG isel folding deficiency:

int X, Y;

void fn1(void)
{
  X = X | (Y << 3);
}

compiles to

fn1:
	movl Y, %eax
	shll $3, %eax
	orl X, %eax
	movl %eax, X
	ret

The problem is the store's chain operand is not the load X but rather
a TokenFactor of the load X and load Y, which prevents the folding.

There are two ways to fix this:

1. The dag combiner can start using alias analysis to realize that y/x
   don't alias, making the store to X not dependent on the load from Y.
2. The generated isel could be made smarter in the case it can't
   disambiguate the pointers.

Number 1 is the preferred solution.

//===---------------------------------------------------------------------===//

DAG combine this into mul A, 8:

int %test(int %A) {
  %B = mul int %A, 8  ;; shift
  %C = add int %B, 7  ;; dead, no demanded bits.
  %D = and int %C, -8 ;; dead once add is gone.
  ret int %D
}

This sort of thing occurs in the alloca lowering code and other places that
are generating alignment of an already aligned value.

//===---------------------------------------------------------------------===//

Turn this into a signed shift right in instcombine:

int f(unsigned x) {
  return x >> 31 ? -1 : 0;
}

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25600
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg01492.html